Few types of transport require as much thinking per mile as sailing - the sailor has to measure the speed and direction of both the water and the wind, which can constantly change, and then manage an array of sails and underwater hydrofoils at the correct angles to create motion in the desired direction. Navigation is its own challenge too, as it's impossible to sail directly into the wind and boats must 'tack' forward in zigzag patterns to make progress. All of which makes it quite remarkable that a group of European enthusiasts have created a Linux-brained autonomous sailboat bristling with sensors and capable of working its way around pre-set race courses or sailing to pretty much any nautical destination without any human intervention. Earlier this year, the ASV 'Roboat' became the first world robotic sailing champion at an event in Austria.